The invention relates to a lighting string comprising two insulated electrical wires extending substantially parallel to and spaced from each other, and a number of pairs of terminals, spaced from each other along the electrical wires, which are adapted to make a cut in the insulation of one of the electrical wires in order to make electric contact with said wire, said terminals serving to accommodate and electrically connect tubular lamps parallel to the electrical wires.
A lighting string of the aforesaid kind is known from the U.S. Pat. No. 4,521,839 (see especially FIGS. 5-7 of the drawings accompanying said patent.
In the known lighting string the electrical wires are kept spaced from each other by an connecting band of plastic material. At the places where the lamps are to be placed a hole is cut out of said band of plastic material, and the ends of a basic part of the terminals are clinched over the electrical wires in the outer ends of the hole, whereby one of the ends is provided with a part cutting into the insulation and whereby the terminals are in electric contact with several of the electrical wires. Each terminal is furthermore provided with a centrally protruding clamping part for accommodating the connecting cap of a lamp.
The known lighting string is supposed to be accommodated in a flexible, light-transmitting tube which is closed at its ends by sealing plugs, one of said plugs having passages for the electrical wires. Thus a lighting device has been realised whereby the lighting string, fixed to a plug, is freely movable in the tube.
In the known lighting string the use of a special ribbon cable is necessary, relatively expensive terminals are needed and its manufacture is time-consuming and therefore costly.
It is noted that from said U.S. patent there is also known a lighting string in which the use of the special ribbon cable is not necessary (see FIGS. 1-3). In that case, however, mounting cylinders provided with a spring are used, which mounting cylinders must be mechanically connected to the electrical wires and whose springs must be electrically connected to the cores of the electrical wires, necessitating the difficult job of removing a small part of the insulation of the electrical wires. It will be apparent that in this case the lighting string will become even costlier, because its manufacture is even more time-consuming and the mounting cylinders will be even more expensive that the above-mentioned terminals.
Accordingly, the purpose of the present invention is to improve the known lighting string such that it can be manufactured less costly and/or that it can be used more versatilely.